The Defense Advanced Research Projects Agency (DARPA) plans to award the first design contracts for the vehicle project — known as Experimental Spaceplane, or XS-1— in May or thereabouts, officials said. Current schedules call for the vessel to get off the ground for the first time in late 2017 and make an orbital test flight the following year.

"The vision here is to break the cycle of escalating space system costs, enable routine space access and hypersonic vehicles," XS-1 program manager Jess Sponable said Feb. 5 during a presentation with NASA's Future In-Space Operations (FISO) working group. (Hypersonic flight is generally defined as anything greater than five times the speed of sound.)